The present invention relates to an apparatus for control of an internal combustion engine, especially for control of the fuel injection and ignition processes and, more particularly, to an apparatus for control of an internal combustion engine comprising a computer in which the angular position of the crankshaft and camshaft is determined by analysis of suitable transmitted signals in order to form a control signal for the injection valves and/or for activating ignition events, in which a crank shaft transmitter wheel with at least one reference mark connected with the crankshaft for production of transmitted signals and a camshaft transmitter wheel with an angle mark extending over 180.degree. connected with the camshaft are each monitored by a receiver.
When and how much fuel should be injected per cylinder and the time for ignition events are calculated in a multi-cylinder internal combustion engine with electronically controlled injection and ignition. So that these computations can be performed in the correct manner, the respective positions of the crankshaft and/or the camshaft or the camshafts of the internal combustion engines must be known. Because of that, as described in German Published Patent Application DE-OS 43 27 218 the crankshaft and camshaft are each connected with a transmitter wheel which has a characteristic surface and is monitored by a receiver. The crankshaft transmitter wheel has a plurality of similar angle marks, which are equally spaced from each other and a reference mark formed by the omission of two angle marks. The camshaft transmitter wheel has a single angle mark, which extends over an arcuate region of 180.degree.. Both transmitter wheels are monitored with the aid of a suitable receiver, whose output signals are analyzed in a control unit or controller.
According to the internal operation of the internal combustion engine the angular positions of the crankshaft and camshaft are not known to the controller. When both shafts have rotated about a predetermined angle and the reference mark and at least one angular mark side of the camshaft is detected, a synchronization can occur and the control pulses for the injection event and the ignition event in the proper phase relationship can be generated and transmitted.